Machines, such as material handlers, typically include a frame of some type, a boom mounted to the frame, and a work tool mounted to an end of the boom. The frame of a material handling machine is typically configured to swing relative to an undercarriage via an electric or hydraulic actuator, such as a swing motor. The boom may further be configured to raise and lower relative to the frame via one or more additional hydraulic actuators. Specialized material handling tools, such as a grapple, may open, close, and be caused to rotate relative to the boom via additional linear actuators, swing motors, and/or geared mechanisms. When the frame swings relative to the undercarriage, the boom and grapple are also caused to swing.
During the swinging motion of the frame, the material load held by the grapple changes orientation relative to the undercarriage. In some instances, such as when handling elongated material loads, this change in orientation is not desired. For example, in the logging industry, logs may be stacked in a parallel orientation relative to a loading container, a railroad car, or a barge. When the logs are subsequently loaded into or on top of the loading container, the material handling machine may perform three steps. First, the machine may use the grapple to pick up the logs. Second, the machine may swing the logs over the loading container. When the logs are originally aligned with the loading container, the swinging motion necessarily causes the logs to rotate out of alignment with the loading container. Accordingly, the machine must then rotate the logs during a third step in order to re-align the logs with the loading container. After realignment, the logs may be lowered and/or released. The re-alignment step decreases productivity and efficiency, particularly when handling bulk quantities of elongated materials. Furthermore, the re-alignment step may also increase collision risks.
One way to avoid the extra re-alignment step is for an operator to manually cause the frame and boom to rotate in a first direction, while simultaneously manually controlling the work tool to counter rotate in a second direction. While possible, this method requires skill and constant operator attention. Further, it can be prone to operator error and/or lead to operator fatigue.
Another rotation method is described in JP2013035651, (“the '651 disclosure”). The '651 disclosure describes a rotating tool and device for turning a suspended load. The '651 disclosure may be useful for rotating suspending loads during a swinging movement of a tower crane boom. The rotating tool may rotate a load that is suspended by a hoist, crane, or a rope. The rotating tool includes an upper hanging connection, a tool frame, a rotation motor, a locking portion, and a lower rotating connection. The lower rotating connection is connected to the rotation motor. In turn, the rotation motor is configured to rotate the lower rotating connection based on operator inputs. Operator inputs may be received by a controller, for example, via a remote operator interface which can then automatically adjust the acceleration and turning speed of the lower rotatable connection in order to stabilize the load.
Although the rotation system of the '651 disclosure may be advantageous for stabilizing rotation of a suspended load, the system still suffers from one or more of the problems described above. For example, the '651 disclosure still requires constant operator attention, which can lead to operator error and/or fatigue.
The disclosed material handling system is directed to overcoming one or more of the problems set forth above.